Question

7 white balls and 3 black balls are placed in a row at random the probability that no two blacks fall are adjacent

Answer 1

Answer:

Hello  !

Since there should be no two adjacent black balls .

We will solve by Gap method

When we place 7 white balls and total gaps available are 8 out of we have to select 3 gaps to place black balls

so the answer is 8C3 = 8!/(5! * 3!) = 56   ........ favourable cases

Sample space = 10!/(7! * 3!) = 120

Probability = 56/120 = 7/15

I hope u r satisfied !

Have a nice day !